Pointing fingers is rude.
W. Eugene Smith, British actor, playwright, and composer, Noel Coward, 1949
In western cultural codes and etiquette, we are taught not to point fingers at people, as it is unacceptable. Quite naturally, being pointed at is perceived as aggressive, accusative, or threatening. The act of putting out the index finger has its negative reputation rooted in not only superstitious beliefs, but also into cultural references like a gun or other weapon. Even if the gesture is not as obvious as the rather similar guns up, it definitely carries the idea of taking aim at someone, in both the literal and figurative senses. War illustrations and particularly calls to arms for World War I in countries such as Great Britain or the United States have reinforced this idea of pointing being a threat and a demand–the recipient is left with no choice.
Weegee, McNamara, ca. 1966
Beyond the symbols and the beliefs, the gesture of pointing has meaning in itself as part of language. Known in linguistics as deictic (or deixis), the act of pointing reveals new information added to the pronounced one. In the contemporary context, pointing fingers at someone, something, or somewhere implies a demonstrative purpose. The gesture is not just used to show but rather to refer. Indeed, the finger is not necessarily demonstrating a physical space or person but may allude to an historical or ideological concept.
In politics, the use of gestures is very ambiguous and in Northern America, pointing fingers at someone is mostly controlled, with some exceptions to the rules. However, during speeches, politicians often point their index fingers in front of them or up in the air. It may be a sign of abstract admonishment, a way to strengthen the political argument, or even a reference to an ideological belief. And the hand and mouth coordination makes the verbal and gestural information complementary.
Wu Yinxian, Comrade Mao Zedong making a speech for the PLA march to southern China, 1945
Chim (David Seymour), [Debate at Writers' Congress, Paris], June 1935
Foremost, pointing fingers is cultural and closely connected to language both in the learning process and in its nonverbal impact on it. For example, for babies it is a way to spatially comprehend the outside world. For Yucatec Maya speakers, pointing is a visual means to replace the missing words for pronouns in the language. It is impossible to refute the importance and even the power of pointing fingers in both the language and our cultural references. And of course in photographs, a subject pointing a finger is also a way to remember that there is a person behind the viewfinder.
Weegee, [Shorty, the Bowery Cherub, New Year's Eve at Sammy's Bar, New York], 1943